1. Field of the Invention
The present invention relates to heat sinks and their retention on heat-generating devices such as electronic packages, and more particularly to a heat sink assembly having a retaining device securely retaining the heat sink on a heat-generating device.
2. Description of Prior Art
Numerous modern electronic devices such as central processing units (CPUs) of computers generate large amounts of heat during operation. The heat must be efficiently removed from the CPU; otherwise, abnormal operation or damage may result. Typically, a retaining device attaches a heat sink on the CPU to remove heat therefrom.
A common kind of retaining device comprises a retention frame and a clip. The retention frame is mounted on a printed circuit board (PCB), and surrounds a CPU that is also mounted on the PCB. The retention frame forms a pair of ears at opposite sides thereof. The clip comprises a central pressing portion pressing a heat sink onto the CPU, and a pair of clamping legs depending from opposite ends of the pressing portion. The legs each define an opening therein, the openings of the legs engagingly receiving the ears of the retention frame. Thus, the heat sink is resiliently attached on the CPU to remove heat therefrom.
With the rapid development of electronics technology, CPUs are now able to process signals at unprecedented high speeds. As a result, CPUs can generate huge amounts of heat. To maintain an acceptably low operating temperature of a high-speed CPU, a heat sink must have great heat dissipation capability. A popular way to achieve this is to simply provide heat sinks that are larger and heavier than previously. However, many conventional retaining devices are not strong enough to securely retain a large, heavy heat sink on the CPU. The heat sink is liable to shift relative to the CPU when the assembly is subjected to vibration or shock during use. This can adversely affect the efficiency of heat removal. The heat sink may even disengage from the CPU altogether.
Accordingly, an object of the present invention is to provide a heat sink assembly having a retaining device which easily and securely fastens a heat sink on a heat-generating device such as an electronic package.
In order to achieve the object set out above, a heat sink assembly in accordance with a preferred embodiment of the present invention comprises a heat sink, a retention frame, a rectangular fastener, four pins and four springs. The heat sink comprises a base defining four bores therein. The frame is secured to a printed circuit board around an electronic package, and defines a pair of through holes. A pair of posts depends from opposite sides of the fastener. The pins are received through the bores of the base and in the fastener. The springs surround the pins respectively between the base and the fastener. The posts are deformably extended through the through holes thereby compressing the springs and sandwiching the base between the retention frame and the springs. The springs cooperatively provide evenly distributed pressing forces on the base. The heat sink is thus easily, firmly and evenly secured to the electronic package.
Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: